Final answer:
Freud's concept of the Superego is what would tell an individual not to indulge in eating cake as it embodies societal morals and pressures that regulate one's impulsive desires.
Step-by-step explanation:
According to Freud, the aspect of Bruce's personality that tells him not to eat the cake is the Superego. The Superego is the part of the unconscious mind that embodies the social pressures to conform, incorporating the values and morals of society learned from parents and others. The Superego represents the social pressure to conform and the internalized values and morals that are instilled by society. It acts as a moral compass, telling Bruce that it is wrong to indulge in the cake and encouraging him to adhere to social norms. It functions to control the Id's impulses, such as those that arise from hunger or desire for pleasurable experiences like eating a cake, especially if doing so would be considered inappropriate or excessive.